ok i have i two question. my first question is my 95 z28 after driving for a hour i was sitting in traffic on a hot day maybe 90 degrees an my oil pressure gage drops in the orange zone and the check gage light came on. i gave the car some gas the pressure went up between the second orange line and the white line. also the check gage light went off as well. my drive home the pressure stay up and the light stay off. also my second question is two days after the oil pressure dropping. when i check my coolant in the radiator it low. i checked the extra coolant tank as well which was full at the min since the car was cool. what could have cause this i never got a warning from the coolant sensor the light works because it come on the car is started. any advice would be helpful. what can cause this to happen.

 

could be bad oil pump/oil filter check to make sure the car isnt leaking any oil under the car

 

Oil pressure will drop as the engine gets hot, but should not drop in the red. You may be using too light a weight oil for summer weather, or the oil may dirty and contaminated with fuel causing the viscosity to drop. 10W40 or 15W40 oil should bring your oil pressure back to normal. Also, on a 11 year old car there is bound to be some bearing wear which will also cause a drop in oil pressure. The oil pump hardly wears out because it is the best lubricated part, but the pump or the drive gear can break from old age, resulting in 0 oil pressure.

As for the coolant problem; what was the coolant temp when the oil pressure dropped?? If there are no visible leaks, I would suspect the system wasn't purged properly and an air pocket was blown out, the radiator cap not holding the right pressure, or improper antifreeze mixture. There is a special procedure that must be followed to fill the radiator and remove the air pockets. Once the radiator is properly filled, any additional coolant should be put in the expansion tank only, as anytime the radiator cap is opened, there is a risk letting air into the system. It is important that you maintain a 50/50 water & antifreeze mix, and that the radiator cap is not leaking and that it is holding the proper pressure. You can have both items checked at most service stations or radiator shop. The antifreeze mix and the pressure cap combine to raise the boiling temperature to around 240 degree. This is very important because the engine normally runs between 220 to 230 degrees on a hot day.

 

well the temp gage was in the middle not sure what the number is maybe 210 or 215 degrees. i do check my coolant level on a normal basis so may be air got into the system. also i just change my oil an use four quarts 10w40 castrol and one quart of lucas heavy duty oil stabilzer. as of right the oil pressure seems ok.